The present invention relates generally to the field of nanotechnology. More specifically, the present invention relates to a method and associated structure for forming a free-standing electrostatically-doped carbon nanotube device.
Carbon nanotubes have attracted a great deal of attention in recent years due to their possibilities for use as nanoscale electronic devices, such as diodes, transistors and semiconductor circuits. Structurally, a carbon nanotube resembles a hexagonal lattice of carbon rolled into a cylinder and may belong to one of two varieties, a single-walled variety and a multi-walled variety. Either of these varieties may, in whole or in part, exhibit the behavior of a metal or a semiconductor material, depending upon their chirality (i.e., conformational geometry).
Carbon nanotubes that exhibit the behavior of a semiconductor material are typically doped using various chemical methods. In other words, different chemicals are used to create p-type (hole majority carrier) regions and n-type (electron majority carrier) regions in the carbon nanotube. This results in a P-N junction that, when an appropriate voltage is applied, emits light (in the case of a light-emitting diode (“LED”)). The chemical methods for doping a carbon nanotube, however, suffer from the problem that the p-type regions and the n-type regions are typically not well characterized, resulting in nanoscale electronic devices with reduced performance characteristics.
Thus, what is needed are a method and associated structure for forming an electrostatically-doped carbon nanotube device having well characterized p-type regions and n-type regions, allowing for the creation of nanoscale electronic devices, such as, for example, photodiodes, photo detectors, photovoltaic devices, sensors, and power devices with enhanced performance characteristics.